Despite little or no previous exposure to dogs, new research suggests that babies understand the meaning of different dog barks. At just 6 months old, infants can match the sounds of an angry snarl and a friendly yap to photos of dogs displaying threatening and welcoming body language.

These new findings come on the heels of a study from the same Brigham Young University lab that showed infants can detect mood swings in the music of Beethoven.

BYU psychology professor Ross Flom, lead author of the study, notes that while dogs and babies sound like a silly mix, these kinds of experiments help to understand how babies learn so rapidly. Well before they have mastered the art of speech, babies can respond to the tone of what is going on around them. Flom said, "Emotion is one of the first things babies pick up on in their social world."

During the experiment, the babies first saw two different pictures of the same dog - one in an aggressive pose and another in a friendly stance. Researchers then played in a random order sound clips of an aggressive and friendly dog bark. While the recordings were being played, the 6-month old babies spent most of their time staring at the appropriate picture. Older babies tended to make the connection instantly upon first glance.

Dan Hyde and Heather Whipple Stephenson conducted the experiment as undergrads along with Prof. Flom. They shared their findings in the journal "Developmental Psychology."